/*
 * Copyright (c) 2007, 2015, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */
/*
 * The Apache Software License, Version 1.1
 *
 *
 * Copyright (c) 1999-2002 The Apache Software Foundation.  All rights
 * reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *
 * 3. The end-user documentation included with the redistribution,
 *    if any, must include the following acknowledgment:
 *       "This product includes software developed by the
 *        Apache Software Foundation (http://www.apache.org/)."
 *    Alternately, this acknowledgment may appear in the software itself,
 *    if and wherever such third-party acknowledgments normally appear.
 *
 * 4. The names "Xerces" and "Apache Software Foundation" must
 *    not be used to endorse or promote products derived from this
 *    software without prior written permission. For written
 *    permission, please contact apache@apache.org.
 *
 * 5. Products derived from this software may not be called "Apache",
 *    nor may "Apache" appear in their name, without prior written
 *    permission of the Apache Software Foundation.
 *
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
 * ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 * ====================================================================
 *
 * This software consists of voluntary contributions made by many
 * individuals on behalf of the Apache Software Foundation and was
 * originally based on software copyright (c) 1999, International
 * Business Machines, Inc., http://www.apache.org.  For more
 * information on the Apache Software Foundation, please see
 * <http://www.apache.org/>.
 */

package com.sun.org.apache.xerces.internal.impl.dtd.models;

import com.sun.org.apache.xerces.internal.xni.QName;

import com.sun.org.apache.xerces.internal.impl.dtd.XMLContentSpec;

/**
 * SimpleContentModel is a derivative of the abstract content model base
 * class that handles a small set of simple content models that are just
 * way overkill to give the DFA treatment.
 * <p>
 * This class handles the following scenarios:
 * <ul>
 * <li> a
 * <li> a?
 * <li> a*
 * <li> a+
 * <li> a,b
 * <li> a|b
 * </ul>
 * <p>
 * These all involve a unary operation with one element type, or a binary
 * operation with two elements. These are very simple and can be checked
 * in a simple way without a DFA and without the overhead of setting up a
 * DFA for such a simple check.
 *
 * @xerces.internal
 */
public class SimpleContentModel
    implements ContentModelValidator {

  //
  // Constants
  //

  /**
   * CHOICE
   */
  public static final short CHOICE = -1;

  /**
   * SEQUENCE
   */
  public static final short SEQUENCE = -1;

  //
  // Data
  //


  /**
   * The element decl pool indices of the first (and optional second)
   * child node. The operation code tells us whether the second child
   * is used or not.
   */
  private QName fFirstChild = new QName();

  /**
   * The element decl pool indices of the first (and optional second)
   * child node. The operation code tells us whether the second child
   * is used or not.
   */
  private QName fSecondChild = new QName();

  /**
   * The operation that this object represents. Since this class only
   * does simple contents, there is only ever a single operation
   * involved (i.e. the children of the operation are always one or
   * two leafs.) This is one of the XMLDTDParams.CONTENTSPECNODE_XXX values.
   */
  private int fOperator;

    /* this is the EquivClassComparator object */
  //private EquivClassComparator comparator = null;

  //
  // Constructors
  //

  /**
   * Constructs a simple content model.
   *
   * @param operator The content model operator.
   * @param firstChild qualified name of the first child
   * @param secondChild qualified name of the second child
   */
  public SimpleContentModel(short operator, QName firstChild, QName secondChild) {
    //
    //  Store away the children and operation. This is all we need to
    //  do the content model check.
    //
    //  The operation is one of the ContentSpecNode.NODE_XXX values!
    //
    fFirstChild.setValues(firstChild);
    if (secondChild != null) {
      fSecondChild.setValues(secondChild);
    } else {
      fSecondChild.clear();
    }
    fOperator = operator;
  }

  //
  // ContentModelValidator methods
  //

  /**
   * Check that the specified content is valid according to this
   * content model. This method can also be called to do 'what if'
   * testing of content models just to see if they would be valid.
   * <p>
   * A value of -1 in the children array indicates a PCDATA node. All other
   * indexes will be positive and represent child elements. The count can be
   * zero, since some elements have the EMPTY content model and that must be
   * confirmed.
   *
   * @param children The children of this element.  Each integer is an index within the
   * <code>StringPool</code> of the child element name.  An index of -1 is used to indicate an
   * occurrence of non-whitespace character data.
   * @param offset Offset into the array where the children starts.
   * @param length The number of entries in the <code>children</code> array.
   * @return The value -1 if fully valid, else the 0 based index of the child that first failed. If
   * the value returned is equal to the number of children, then the specified children are valid
   * but additional content is required to reach a valid ending state.
   */
  public int validate(QName[] children, int offset, int length) {

    //
    //  According to the type of operation, we do the correct type of
    //  content check.
    //
    switch (fOperator) {
      case XMLContentSpec.CONTENTSPECNODE_LEAF:
        // If there is not a child, then report an error at index 0
        if (length == 0) {
          return 0;
        }

        // If the 0th child is not the right kind, report an error at 0
        if (children[offset].rawname != fFirstChild.rawname) {
          return 0;
        }

        // If more than one child, report an error at index 1
        if (length > 1) {
          return 1;
        }
        break;

      case XMLContentSpec.CONTENTSPECNODE_ZERO_OR_ONE:
        //
        //  If there is one child, make sure its the right type. If not,
        //  then its an error at index 0.
        //
        if (length == 1) {
          if (children[offset].rawname != fFirstChild.rawname) {
            return 0;
          }
        }

        //
        //  If the child count is greater than one, then obviously
        //  bad, so report an error at index 1.
        //
        if (length > 1) {
          return 1;
        }
        break;

      case XMLContentSpec.CONTENTSPECNODE_ZERO_OR_MORE:
        //
        //  If the child count is zero, that's fine. If its more than
        //  zero, then make sure that all children are of the element
        //  type that we stored. If not, report the index of the first
        //  failed one.
        //
        if (length > 0) {
          for (int index = 0; index < length; index++) {
            if (children[offset + index].rawname != fFirstChild.rawname) {
              return index;
            }
          }
        }
        break;

      case XMLContentSpec.CONTENTSPECNODE_ONE_OR_MORE:
        //
        //  If the child count is zero, that's an error so report
        //  an error at index 0.
        //
        if (length == 0) {
          return 0;
        }

        //
        //  Otherwise we have to check them all to make sure that they
        //  are of the correct child type. If not, then report the index
        //  of the first one that is not.
        //
        for (int index = 0; index < length; index++) {
          if (children[offset + index].rawname != fFirstChild.rawname) {
            return index;
          }
        }
        break;

      case XMLContentSpec.CONTENTSPECNODE_CHOICE:
        //
        //  There must be one and only one child, so if the element count
        //  is zero, return an error at index 0.
        //
        if (length == 0) {
          return 0;
        }

        // If the zeroth element isn't one of our choices, error at 0
        if ((children[offset].rawname != fFirstChild.rawname) &&
            (children[offset].rawname != fSecondChild.rawname)) {
          return 0;
        }

        // If there is more than one element, then an error at 1
        if (length > 1) {
          return 1;
        }
        break;

      case XMLContentSpec.CONTENTSPECNODE_SEQ:
        //
        //  There must be two children and they must be the two values
        //  we stored, in the stored order.
        //
        if (length == 2) {
          if (children[offset].rawname != fFirstChild.rawname) {
            return 0;
          }
          if (children[offset + 1].rawname != fSecondChild.rawname) {
            return 1;
          }
        } else {
          if (length > 2) {
            return 2;
          }

          return length;
        }

        break;

      default:
        throw new RuntimeException("ImplementationMessages.VAL_CST");
    }

    // We survived, so return success status
    return -1;
  } // validate

} // class SimpleContentModel
